These teachings relate generally to optical systems that can read image and imager pupil from a shared location to two or more optical systems.
In common aperture systems, it is often desirable to provide access to a shared optical component, pupil, imager, or system for two or more optical systems simultaneously. This can be difficult to achieve as a result of tradeoffs between the back focal distance requirements of the individual systems, obstructions due to optical or mechanical components, and other concerns.